Notoraja alisae, Séret & Last, 2012

Séret, Bernard & Last, Peter R., 2012, New deep water skates of the genus Notoraja Ishiyama, 1958 (Rajoidei, Arhynchobatidae) from the southwest Pacific, Zoosystema 34 (2), pp. 319-341 : 320-327

Notoraja alisae n. sp.

( Figs 1-8 ; Tables 1, 3)

Rajidae NG sp. ♀ – Last in Williams et al. 2006: listed in appendix 1, p. 36; 4 colour photos in Appendix 8, p. 6, of female 479 mm TL ( NMNZ P 39619) .

HOLOTYPE. — MNHN 1997-3598 , adult male 515 mm TL, cruise HALIPRO 1, R / V Alis , stn CH 876, northern Norfolk Ridge, 23°10.41’S, 166°49.16’E, 870 m depth, 31.III.1994, bottom trawl.

PARATYPES. — 2 specimens. MNHN 1977-3599, male 340 mm TL, cruise HALIPRO 1, R / V Alis, stn CH 876, 23°10.41’S, 166°49.16’E, 870 m depth, 31.III.1994, bottom trawl.— MNHN 1997-3600, female 492 mm TL, cruise HALIPRO 2, R / V Tangaroa , stn BT02, northern Norfolk Ridge, 23°16’S, 167°49’E, 1025/ 1049 m depth, 5.XI.1996, bottom trawl.

ADDITIONAL MATERIAL. — 4 dark specimens. MNHN 1997-3601, adult male 533 mm TL, cruise HALIPRO 2, R/V Tangaroa , stn BT43, Norfolk Ridge, Seamount “Désespoir”, 25°41’S, 167°12’E, 1030/ 1320 m depth, bottom trawl, 15.XI.1996. — MNHN 1997-3597, female 545 mm TL, MUSORTOM 8, R/V Alis, Vanuatu, stn CP1008, 18°53.29’S, 168°52.65’E, 919/ 1000 m depth, beam trawl, 25.IX.1994. — NMNZ P 39619, female 479 mmTL, NORZANZ cruise, R/V Tangaroa , stn 155,

southern Norfolk Ridge, 34°34.81’S, 168°57.79’E, 813/ 1000 m depth, bottom trawl, 4.VI.2003. — MNHN 2003-1780, adult male 460 mm TL, NORFANZ cruise, R/V Tangaroa , stn 159, southern Norfolk Ridge, 35°8.13’S, 169°28.37’E, 868/ 972 m depth, bottom trawl, 4.VI.2003.

DISTRIBUTION. — Only known from the northern sector of the Norfolk Ridge (New Caledonian EEZ) from 870 to 1049 m depth. The dark form exhibits a wider latitudinal distribution, from the southern Norfolk Ridge (35°8’S) in New Zealand’s EEZ to Espiritu Santo in Vanuatu (c. 18°53’S) ( Fig. 18 ).

ETYMOLOGY. — From the name of the French research vessel Alis of the Institut de Recherche pour le Développement (IRD) in Nouméa, with which numerous exploratory cruises have been performed in New Caledonian EEZ in the last decades; the name of the ship Alis came from the name of a local wind.

DIAGNOSIS. — A medium-size species of Notoraja with the following combination of characters:disc wider than long, width 50.9-55.5% TL, length 43.8-45.7% TL; dorsal head length 17.1-19.0% TL; interspiracular distance 6.2-6.7% TL, internasal distance 7.0-8.5% TL, preorbital length 2.7-3.1 times orbit length and 3.4-3.6 interorbital; tail width at pelvic-fin axil 1.5-1.6 times its height; single rudimentary preorbital thorn; dorsal and ventral surfaces of disc entirely velvety, covered with fine denticles; tail long and slender, entirely velvety and without enlarged thorns; lateral tail folds variably expanded posteriorly, their width sometimes greater than tail width at level of second dorsal fin; nasal lobes expanded, width of nasal curtain 8.1-9.8% TL; anterior pelvic-fin lobe shorter that posterior lobe; dorsal and ventral surfaces pale greyish brown; total pectoral-fin radials 63; monospondylous centra 24-25, total diplospondylous centra 112-117, total centra 136-142.

DESCRIPTION

Disc heart-shaped (more so in adult male than female and young), 1.15 times as broad as long in male holotype (1.16-1.21 in paratypes); maximum angle in front of spiracles 83° (98-99°); anterior margin slightly concave on either side of tip of snout, slightly convex from anterior extension of propterygium to anterior margin of orbit, concave to level of spiracle; outer corner broadly rounded; posterolateral margin moderately convex in males; anterolateral margins of disc very slightly undulate in female and juvenile. Axis of greatest width 56% (59-60%) of disc length. Preorbital snout length 2.66 (2.58-3.09) times orbit length, 3.64 (3.11-3.38) times interorbital width; preoral snout length 1.63 (1.58-1.74) times internarial distance. Orbit diameter 1.37 (1.09-1.20) times interorbital distance, and 2.32 (1.59-2.08) times length of spiracles. Nasal lobes moderately expanded and rounded, posterior margin shortly and flabby fringed. Mouth relatively wide, its width more than 66% of maximum width of nasal curtain. Upper jaw of male slightly indented at symphysis (not indented in female and moderately arched); upper and lower jaws slightly arched on either side of symphysis. Teeth with acutely pointed cusps and arranged in parallel rows in mature male holotype (plate-like with short cusps and arranged in quincunx in female and juvenile male paratypes). Distance between first gill slits 1.51 (1.73-1.77) times larger than distance between nostrils; distance between fifth gill slits 1.00 (1.21-1.29) times larger than distance between nostrils.

Pelvic fins deeply incised with lobes connected by radials and membranes, anterior lobe moderately long, reaching to about posterior third of posterior lobe (further in paratypes), finger-like with blunt tip; posterior lobe with convex lateral margins, its posterior margin crenate due to extension of posterior radials. Tail narrow at base, variably depressed over length; strongly convex dorsally, slightly convex ventrally; tapering gradually posteriorly; tail width at axils of pelvic fins 2.44 (2.34-2.60) times width at its midlength, 2.65 (3.38-3.71) times its width at dorsal-fin origin respectively; length from rear of cloaca 1.52 (1.45-1.60) times distance from tip of snout to rear of cloaca; width at first dorsal origin 1.53 (1.62-1.71) times height at axils of pelvic fin; width at first dorsal-fin origin 1.73 (1.43- 1.54) times its height; lateral skin folds originating near midlength of tail, extending to distal half of epichordal caudal-fin lobe; folds slightly broadening distally (more so in paratypes), but always narrower than tail width. Dorsal fins of similar shape and size; rather short and moderately tall with evenly convex anterior margins, straight or slightly convex posterior margins and a pointed rear tips; separated by a short interspace, 41% (23-36%) length of first dorsal-fin base. Epichordal caudal-fin lobe developed, separated by narrow interspace from and distinctly longer than second dorsal-fin base; hypochordal caudal lobe very low, originating near end of lateral fold, confluent with epichordal lobe. Both dorsal and ventral surfaces entirely covered with fine, densely spaced, dermal denticles; denticles bristle-like, erect, with almost straight pointed crowns. Single greatly reduced preorbital thorn (even very small in juvenile). Tail totally velvety, lacking enlarged thorns; median thorns very small, confined mainly to anterior tail, barely taller than largest denticles adjacent. Alar thorns in three or four irregular rows; posteromedially oriented, with elongated bases, oblique slightly curved crowns, exposed on integument. Malar thorn patch small, on outer anterior margin and merging with those of alar patch; noticeably larger than adjacent denticles, with oval conical base and fine curved cusp.

Claspers long and very slender, glans depressed, but little expanded; with inner dorsal components slit, cleft and pseudorhipidion, and inner ventral components pela, projection and spike. Claspers partially covered with lines of very fine dermal denticles. Tooth rows in upper jaw 38 in male holotype (34-43 in paratypes); lower jaw 40 (33-38). Pectoral propterygial radials 28 (28); mesopterygial radials 11-12 (11-12); metapterygial radials 22-23 (21-24); total radials 62 (61-63). Monospondylous centra 24 (24-25); diplospondylous predorsal centra 77 (78-82); predorsal centra 101 (102-107); caudal centra 35 (35-37); total diplospondylous centra 112 (115-117); total centra 136 (139-142).

Colour (in preservative)

Dorsal surface plain pale greyish brown. Ventral surface lighter, yellowish with faint whitish spots at level of pores of the lateral line system.

Size

Males reach at least 515 mm TL (adult male holotype), and females to at least 545 mm TL (based on dark female from Vanuatu, MNHN 1997-3597).

REMARKS This velcro skate is well represented by specimens. A group of unusually dark individuals are tentatively assigned to Notoraja alisae n. sp., but were excluded from the type series (cf. additional material; Figs 6-8 ; Tables 1, 3)pending further investigation.They closely resemble the typical pale form of this species, except for their darker colouration and slight morphometric differences.These dark specimens are: darker dorsally (plain dark greyish with darker eyes, posterior pelvicfin lobes and lateral tail folds); the ventral surface is dark grey, particularly on the central part of disc; their pale ventral pores are more pronounced, forming lines of light spots along branches of the lateral line system; their disc is slightly longer (46.6-47.8% TL vs 43.8-45.7% TL); precloacal length slightly longer (40.0-41.7% TL vs 37.7-39.4% TL); tail somewhat shorter (distance from the cloaca to the first dorsal-fin origin 43.7-44.8%TL vs 46.1-48.5% TL, to the second dorsal-fin origin 47.7-49.0%TL vs 50.9-52.1%TL, to the caudal-fin origin 51.2-53.3% TL vs 53.3-58.6% TL, and to tail tip 56.8-58.0% TL vs 57.1-60.3%TL). Although the tail is shorter, its predorsal length is longer (distance first dorsal-fin origin to tip of tail 4.1-5.3% TL vs 3.4-4.2% TL). No meristic differences nor differences in the external components of the clasper were found.

Squamation is similar in both pale and dark specimens, however a dark mature male (MNHN 1997- 3601) has coarser dermal denticles arranged in small, irregular patches and lines (similar, but less pronounced, lines are present on the posterior pectoral fins of the holotype), and the preorbital thorns are not apparent in a dark female (MNHN 1997-3597). Pending collection and examination of more specimens of the dark form, we consider these slight differences to be intraspecific variations of N. alisae n. sp.

Figures

FIG. 1. — Notoraja alisae n.sp.,holotype (MNHN 1997-3598,male adult 515 mm TL):A, dorsal surface;B, ventral surface.Scale bar:10 cm.

FIG. 2. — Dorsal head of Notoraja alisae n. sp., holotype (MNHN 1997-3598, male adult 515 mm TL). Scale bar: 1 cm.

FIG. 18.— Oronasal region of Notoraja longiventralis n.sp., holotype (MNHN 1999-0449, male juvenile 434 mm TL). Scale bar: 1 cm.

FIG. 6. — Notoraja alisae n. sp., dark form (MNHN 1997-3601, male adult 533 mm TL): A, dorsal surface; B, ventral surface. Scale bar: 10 cm.

FIG. 7. — Dorsal head of Notoraja alisae n. sp., dark form (MNHN 1997-3601, male adult 533 mm TL). Scale bar: 1 cm.